An electrochemical fuel cell is a device that converts fuel and an oxidant to electricity, reaction product, and heat. Fuel cells commonly are configured to convert hydrogen and oxygen into water and electricity. In such fuel cells, the hydrogen is the fuel, the oxygen is the oxidant, and the water is the reaction product.
The amount of electricity produced by a single fuel cell may be supplemented by connecting several fuel cells together. Fuel cells connected together in series are often referred to as a fuel cell stack. Some fuel cell stacks include membrane-electrode assemblies that are separated by electrically conductive bipolar plates that electrically connect a cathode of one fuel cell to an anode of another. The plates also usually provide structural support to adjacent membrane-electrode assemblies. Furthermore, the plates commonly provide fuel and an oxidant to membrane-electrode assemblies while removing water and heat therefrom.